224 MAZATLAN UNIVALVES 



plaited spiral frill, prickly inside. Between this and the outer 

 margin are 4 6 (generally 5) fine emerald necklaces, supported 

 on slender spiral ribs, with deeply channeled interspaces. The 

 margin and the body of the operculum are white. The oper- 

 culum of its neighbour, C. saxosum (Panama, C. B. Adams, 

 S. W. Mexico, P. P. C.) is formed on a much coarser plan, 

 with the central callus not covering the ^umbilicus, the frill 

 rather granular than plaited, the three rows of necklaces close 

 together, without deep channels, and with large granules on 

 the margin. All the Mazatlan shells were of the typical form, 

 with the spire elevated, whirls well rounded, with distant rows 

 of nodules. Whether the C. f. depressum is a variety of this 

 form, (as I described it in the P. Z. S., copying Heeve's error 

 in the name, and not aware that Kiener had figured it,*) 

 or another species, cannot be decided without a knowledge 

 of the operculum. The shell is distinguished from all varieties 

 of C. saxosum, by the non-corrugation of its surface. Long. 2 '56, 

 lat. 2'5, div. 90 \ 

 JETab. Punta St. Elena, Cuming. Mazatlan; abundant; 



L'pool Col. San^Diego, Lieut. Green. Sitka, WosnessensJci, 



Middendorff. 



Tablet 1081 contains the largest specimen, in its natural 

 rough state. 1082, the sp. which suffered least from hot acid. 

 1083, 6 opercula of different ages, and of exquisite beauty. 



GENUS PHASIANELLA, Lam. 



Lam. Phil. Zool. 1809. Phil. Handb. Conch, p. 205. 

 Eutropia, (Humph.) Gray, 1847. JET. fy A. Ad. Gen. vol. i, 



p. 389. 

 Phasianus, Montf. 1810. Trie olia, Risso, 1826. 



* 



283. PHASIANELLA PEEFOEATA, Phil. 



Zeit. f. Mai. 1848, p. 164, no. ^.Kust. Mart. p. 20, sp. 24, 

 pi. 4, f. 14. 



Comp. Phasianella tessellata, Seek, 1838, Pot. et. Mich. Gall. 

 vol. i. p. 312, pi. 29, f. 7, S. C. B. Ad. Contr. Conch. 1850, 

 p. Q7Phil. in Kust. Mart. p. 18, sp. 22, pi. 4, f. 12. =Ph. 

 minuta, Anton, 1839, Verz. p. 60, no. 2129, (non Sow.) =Ph. 



* I have seen no letter-press in explanation of the figure, nor are any dates 

 given in Kiener's monographs, by which questions of priority can be determined, 



